System and method for reducing peak and off-peak electricity demand by monitoring, controlling and metering lighting in a facility

ABSTRACT

A method of reducing electricity usage during peak demand periods includes the steps of establishing predetermined load reduction criteria representative of a desire by a power provider to reduce loading on an electricity supply grid, and coordinating with a facility having lighting equipment to permit the power provider to turn-off one or more of the lighting equipment by sending instructions to a master controller at the facility in response to the predetermined load reduction criteria, and establishing a list of lighting equipment to be turned-off in response to the instructions, and configuring the master controller to send an override control signal to the lighting equipment to implement the instructions, and configuring the lighting equipment to send a response signal to the master controller providing a status of the lighting equipment.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This application is a continuation of U.S. Nonprovisional applicationSer. No. 13/609,096 filed Sep. 10, 2012, which is a continuation of U.S.application Ser. No. 12/057,217, filed Mar. 27, 2008, incorporatedherein by reference in its entirety.

FIELD

The field of the disclosure relates generally to reduction in energyusage. More specifically, the disclosure relates to systems and methodsfor intelligent monitoring, controlling and metering of lightingequipment in a facility to reduce consumption of electricity during peakand off-peak demand periods.

BACKGROUND

This section is intended to provide a background or context to theinvention recited in the claims. The description herein may includeconcepts that could be pursued, but are not necessarily ones that havebeen previously conceived or pursued. Therefore, unless otherwiseindicated herein, what is described in this section is not prior art tothe description and claims in this application and is not admitted to beprior art by inclusion in this section.

According to the International Energy Outlook 2006, Report No.DOE/EIA-0484(2006) from the U.S. Dept. of Energy, the world's total netelectricity consumption is expected to more than double during theperiod 2003-2030. Much of the electricity is expected to be used toprovide industrial, institutional, commercial, warehouse and residentiallighting. Adoption of energy-efficient technologies can help to conserveelectricity thereby slowing the growth in both the “base demand” and“peak demand” components of electricity demand. Base demand is thesteady-state, or average, demand for electricity, while peak demandoccurs when the demand for electricity is the greatest, for example,during a hot summer day when electricity use for air conditioning isvery high. Reducing either type of demand is desirable, but a reductionin peak demand generally is more valuable because of the relatively highunit cost of the capacity required to provide the peak demand.

Many facilities (e.g. commercial, residential, industrial,institutional, warehouses, etc.) typically include (or are beingmodified to include) artificial lighting devices such as high intensityfluorescent (“HIF”) lighting fixtures that reduce the amount ofelectricity consumed in comparison to other less efficient types ofartificial lighting such as high intensity discharge (“HID”) lighting.Although HIF lighting equipment reduces the consumption of electricityrequired for operation, it is desirable to further reduce theelectricity consumed by HIF lighting equipment in a facility. Suchlighting devices are often configured for control using relativelysimplistic control schemes, such as “on” or “idle” during periods wherethe facility is regularly occupied, and “off” or “standby” when thefacility is regularly unoccupied (typically referred to as thefacility's “usage pattern”). It would be desirable to reduce consumptionof energy by providing a system and method to permit a power provider totrim or shed certain predetermined loads in cooperation with a facilityduring peak demand periods. It would also be desirable to reduceconsumption of energy during peak and off-peak demand periods by usingsensing and control devices to intelligently monitor an environmentwithin a facility to turn-off or reduce power to HIF lighting equipmentin the facility, when operation of the equipment is unnecessary,particularly during regularly occupied periods which often correspond topeak demand times for the supplier of the electricity (e.g. utilities,etc.).

What is needed is a system and method for reducing peak and off-peakelectricity usage in a facility by intelligently monitoring the need foroperation of HIF lighting equipment in a facility, and turning-off theHIF lighting equipment during periods when operation of the HIF lightingequipment is determined to be unnecessary, or when peak demand electriccapacity is limited and dictates a reduction in demand. What is alsoneeded is a system and method to reduce electricity usage during peakdemand periods by providing a signal from an electricity supplier to theHIF lighting equipment to turn-off certain equipment on an as-neededbasis (e.g. during unplanned or unforeseen reductions in capacity, etc.)according to a pre-established plan with the facility to accomplish peakelectric supply capacity objectives. What is further needed is a systemand method to reduce electricity usage during peak demand periods byautomatically providing a signal from an electricity supplier to the HIFlighting equipment to turn-off certain equipment, in accordance with apre-established plan with the facility, in response to decreasingcapacity margins during peak demand periods. What is further needed aresuitable sensors operable to monitor the need for operation of the HIFlighting equipment during peak or off-peak demand periods at variouslocations within the facility. What is also needed is a control deviceoperable to receive an indication of the need for operation of the HIFlighting equipment and to provide a demand-based control signal toturn-off such equipment during periods when operation of the HIFlighting equipment is unnecessary, or override the usage of suchequipment when peak demand capacity limitations dictate a reduction inusage. What is further needed is a control device that logs (e.g.records, tracks, trends) the time, duration and amount of electricitythat is “saved” by reducing the operation of such equipment, andprovides output data to determine the cost savings provided by theintelligent monitoring, relative to the facility's typical usagepattern. What is further needed is a system that communicates with apower provider to permit a user, such as a power provider, to “trim” or“shed” certain loads during peak demand periods by overriding thedemand-based control signals. What is further needed is a system thatprovides a data log of energy reduction (i.e. total reduction andreduction for individual devices) achieved by use of the system, both ona cumulative basis for a designated period of time, and on aninstantaneous basis for confirmation by a power provider.

Accordingly, it would be desirable to provide a system and method thatpermits an energy user and/or a power provider to actively manage andreduce the energy usage in a facility required by HIF lightingequipment, particularly during periods of peak and off-peak demand.

SUMMARY

In one exemplary embodiment, a method of reducing electricity usageduring peak demand periods is provided. The method includes the steps of(a) establishing one or more predetermined load reduction criteria thatare representative of a desire by a power provider to reduce loading onan electricity supply grid, and (b) coordinating with a facility havinga plurality of HIF lighting equipment to permit the power provider toturn-off one or more of the HIF lighting equipment by sendinginstructions to a master controller at the facility in response to anoccurrence of one or more of the predetermined load reduction criteria,and (c) establishing a list of one or more of the HIF lighting equipmentto be turned-off in response to the instructions, and (d) configuringthe master controller to send an override control signal to the one ormore of the HIF lighting equipment to implement the instructions, and(e) configuring the one or more of the HIF lighting equipment to send aresponse signal to the master controller providing a status of the HIFlighting equipment.

In another exemplary embodiment, system for monitoring, controlling andmetering HIF lighting fixtures in a facility. The system includes atleast one sensor operable to measure a parameter within an interiorspace of the facility and to send a sensor signal representative of theparameter to a master controller. A plurality of local transceiver unitscommunicate with the master controller, where each local transceiverunit is configured for installation on each of the HIF lightingfixtures. The master controller communicates with the sensor and thelocal transceiver units, and operates to provide a control signal to thelocal transceiver units to control operation of the HIF lightingfixtures according to a time-based scheme, and process the sensor signaland provide a control signal to control operation of one or more of theHIF lighting fixtures according to a demand-based scheme, and receiveand process override instructions and provide an override control signalto control operation of one or more of the HIF lighting fixturesaccording to an override-based scheme, and receive a signal from thelocal transceiver units representative of a status of the electricaldevice associated with the transceiver units, and quantify a reductionin power usage achieved by the demand-based scheme and theoverride-based scheme, and transmit data representative of the reductionin power usage to a user.

In another exemplary embodiment, a method of method for monitoring,controlling and metering HIF lighting fixtures in a facility isprovided. The method includes controlling operation of the HIF lightingfixtures by transmitting a time-based control signal to one or more ofthe HIF lighting fixtures according to a time-based control scheme, andmodifying the time-based control scheme by transmitting a demand-basedcontrol signals to one or more of the HIF lighting fixtures, andoverriding the time-based control signals and the demand-based controlsignals by providing an override signal to one or more of the HIFlighting fixtures, and quantifying a reduction in power obtained bycontrolling the HIF lighting fixtures with any one or more of thetime-based control signal, the demand-based signal and the overridesignal.

In a further exemplary embodiment, a system for monitoring, controllingand metering a plurality of HIF lighting fixtures in a facility isprovided. The system includes at least one sensor operable to measure aparameter within an interior space of the facility and to send sensorsignals representative of the parameter to a master controller. Aplurality of local transceiver units are configured for installation onthe plurality of HIF lighting fixtures, where the local transceiverunits receive control signals from the master controller to operate anassociated HIF lighting fixture and to send response signals to themaster controller. The master controller communicates with the sensorand the local transceiver units, and operates to provide a controlsignal to the local transceiver units to control operation of the HIFlighting fixtures according to a predetermined control schedule, andprovide a demand-based control signal to operate the HIF lightingfixtures in response to the sensor signals representative of theparameter, and define actual power reduction data associated withcontrol of the HIF lighting fixtures by the demand-based control signal;and transmit the power reduction data to a user.

Other principal features and advantages of the invention will becomeapparent to those skilled in the art upon review of the followingdrawings, the detailed description, and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the invention will hereafter be described withreference to the accompanying drawings, wherein like numerals denotelike elements.

FIG. 1 depicts a schematic diagram of a system for monitoring,controlling and metering a plurality of HIF lighting fixtures in afacility in accordance with an exemplary embodiment.

FIG. 2 depicts a schematic diagram of a system for monitoring,controlling and metering a plurality of HIF lighting fixtures in afacility in accordance with another exemplary embodiment.

FIG. 3 depicts a schematic diagram of a system for monitoring,controlling and metering a plurality of HIF lighting fixtures in afacility in accordance with a further exemplary embodiment.

FIG. 4 depicts a block diagram of a method for monitoring, controllingand metering a plurality of HIF lighting fixtures in a facility inaccordance with an exemplary embodiment.

FIG. 5 depicts a block diagram of a method for reducing electricityusage during peak demand periods in accordance with an exemplaryembodiment.

DETAILED DESCRIPTION

With reference to FIG. 1, a block diagram of an intelligent system 10for monitoring, controlling and metering electrically-operated (e.g.electricity consuming) equipment shown as HIF lighting fixtures in afacility 12 is shown in accordance with an exemplary embodiment. Thesystem 10 is shown to include a master controller 20, a mastertransceiver 40, a sensor 50, a group of HIF lighting fixtures 60, and alocal transceiver unit 70 associated with the HIF lighting fixtures 60.Although only one sensor is shown to be associated with the HIF lightingfixtures in one environment (or interior space), it is understood thatany number of sensors (operable to monitor any of a wide variety ofparameters in one or more interior spaces within the facility) may beprovided for operating the HIF lighting fixtures in one or moredesignated spaces or environments within the facility.

The master controller 20 is programmable with a desired usage pattern(e.g. control schedule, operation schedule, time schedule, etc.) for theapplicable electrically-operated equipment in the facility andautomatically generates a time-based control signal 42 to be sent fromthe master transceiver 40 to the local transceiver unit(s) 70 associatedwith each of the applicable HIF lighting fixtures 60 to controloperation of the fixtures according to the usage pattern (e.g. turn onat a specified time, turn off at a specified time, etc.). The mastercontroller 20 is also operable to automatically “learn” a new usagepattern based on an on-going pattern of demand-based control signals 44from the master controller 20, based on demand signals received from thesensor 50. The master controller may also be manually programmed withnew (or modified) usage patterns, as may be determined by a manager ofthe facility (or other appropriate entity).

In order to provide for intelligent control of the HIF lightingequipment, the master controller 20 is also operable to reduce powerconsumption during peak and off-peak power demand periods by monitoringthe need for operation (e.g. “demand”) of the HIF lighting fixtures (asindicated by appropriate signal(s) received from the sensors) andgenerating a demand-based control signal 44 that is sent from the mastertransceiver 40 to the local transceiver units 70 for operation of theHIF lighting fixtures 60 in a manner intended to reduce powerconsumption during the peak and/or off-peak demand periods (e.g.turn-off, turn-on, etc.).

To further provide for intelligent control of the HIF lightingequipment, the master controller 20 may also receive instructions froman external entity (e.g. shown for example as a power provider 14, etc.)to shape or manage peak loading by “trimming” or “shedding” load (e.g.during peak demand periods, or during other periods when power supplycapacity is limited, such as when a base load generating plant is takenoff-line, etc.) by generating an override control signal 46 to be sentfrom the master transceiver 40 to the local transceiver units 70 foroverriding the time-based control signals 42 and/or the demand-basedcontrol signals 44 and turning certain designated HIF lighting fixturesoff. According to one embodiment, the override control signal 46 may beselectively transmitted to the fixtures on an as-needed or case-by-casebasis to permit selective/manual management of loading and capacity of apower grid during peak demand periods. According to another embodiment,the override control signal 46 may be automatically transmitted to thefixtures upon the occurrence of certain predetermined criteria, such asa reduction in available capacity to a certain level or percentage, or arate of reduction in available capacity that exceeds a certain setpoint,etc. The criteria for initiation of the override control signal 46 areintended to be established in advance between the power provider and thefacility manager and implemented according to a predeterminedarrangement. According to such an arrangement, certain designated HIFlighting fixtures may be preprogrammed into the master controller 20 bythe facility manager (or others) according to the criticality ofoperation of the HIF lighting fixtures, and may be provided in “stages”or the like according to an amount of demand reduction that is desired.The local transceiver units actuate the HIF lighting fixtures accordingto the control signal(s) (i.e. turn-on, turn-off, etc.) and then send areturn signal corresponding to the particular HIF lighting fixture torespond to the master controller indicating that the action has beenaccomplished and to provide a status of each HIF lighting fixture (e.g.on, off, etc.). The term “power provider” as used herein is intended toinclude (as applicable) any supplier, distributor or aggregator ofelectrical power to a user, including but not limited to an electricpower aggregator, a utility, a utility generator, an electric powergenerator, an electric power distributor, etc.

The master controller 20 receives the return signal 72 from the localtransceiver unit(s) 70 and is intended to provide “intelligent metering”of each of the HIF lighting fixtures 60 in the facility 12 by logging(e.g. tracking, recording, trending, etc.) the power reduction achievedby reducing operation of the HIF lighting fixtures 60 (e.g. during peakdemand periods relative to the facility's usage pattern as accomplishedby monitoring within the facility 10, or during any reduced capacityperiod as requested/instructed by the power provider, etc.) and providesdata for each HIF lighting fixture to a user (e.g. facility manager,power provider, third-party power reduction service provider, etc.) toconfirm the action requested by an override control signal has beenaccomplished for shaping or managing peak demand, and to quantify thepower reduction and/or the corresponding economic savings. The data isprovided in a cumulative format to provide a total savings over apredetermined period of time. The data is also provided instantaneouslyfor confirmation of the status of each of the HIF lighting fixtures(e.g. on, off, etc.) by the user.

The master controller 20 may be a custom device that is programmed withthe desired algorithms and functionality to monitor and controloperation of, and to provide intelligent metering of, the HIF lightingfixtures. Alternatively, the master controller may be a commerciallyavailable product.

The master controller 20 is operable in a “normal” mode and an“override” mode for control of the HIF lighting fixtures 60. For“normal” modes of control, the master controller 20 operates accordingto both a time-based control scheme and a demand-based control scheme toreduce electricity usage during both peak and off-peak demand periods.In the time-based control scheme, the master controller 20 controlsoperation of the HIF lighting fixtures 60 according to the usage pattern(i.e. on a time-based schedule, etc.) to operate (e.g.energize/de-energize, turn on/off, etc.) the HIF lighting fixtures 60.The usage pattern provides a “baseline” operation control scheme for theHIF lighting fixtures 60 that is time or schedule based, and may beregularly updated (manually or automatically) to reflect changing usagepatterns for the HIF lighting fixtures 60. For example, the time basedcontrol scheme may reduce off-peak demand by reducing the scope/durationof the usage pattern and conserve energy during evening and nighttimehours.

In the demand-based control scheme, the master controller 20 monitorsand controls the designated HIF lighting fixtures 60 within the facility12 based on signals received from various sensors 50. Each sensor isoperable to monitor any one or more of a wide variety of parametersassociated within a predefined interior space 16 (e.g. designatedenvironment, room, etc.) within the facility 12, such as but not limitedto, ambient light level, motion, temperature, sound, etc., and provide asensor output signal 52 associated with the parameter to the mastercontroller 20. Alternatively, a switch (e.g. pushbutton, etc.) may beprovided so that a user can manually initiate an output signal. Thesensor output signal 52 may be transmitted using a network that iswired, or may be wireless. According to one embodiment as shown forexample in FIG. 2, the sensor 50 is operable to monitor ambient lightlevel (e.g. through windows, light-pipes, skylights, etc.) and/or motionwithin the interior space 16 and to provide a sensor output signal 52 tothe master controller 20 via a hardwire network 54. The mastercontroller 20 processes the sensor output signal(s) 52 according to apreprogrammed algorithm having logic steps that determine the need (e.g.demand) for operation of the HIF lighting fixtures 60, based on thefacility usage pattern and the parameters monitored by the sensor(s) 50,and defines or generates a demand-based control signal 44 to betransmitted from the master transceiver 40 to the appropriate localtransceiver unit(s) 70 to control operation of the HIF lighting fixtures60. For example, the demand based control scheme may reduce peak demandor off-peak demand depending on when the HIF fixtures are turned-off(e.g. by turning-off the HIF fixtures due to ambient light level duringdaytime hours, or by turning-off the HIF fixtures due to absence ofmotion during evening/nighttime hours, etc.).

According to the embodiment illustrated in FIGS. 1-3, a localtransceiver unit 70 is provided on each of the HIF lighting fixtures 60and intended to be controlled by the master controller 20, and eachlocal transceiver unit 70 includes a unique address corresponding to aparticular HIF lighting fixture 60 that is recognized by the mastercontroller 20. According to one embodiment, each local transceiver unit70 includes multiple switches (e.g. relays, etc.) for operation of theHIF lighting fixtures. For example, in HIF lighting fixtures having twoballasts, one local transceiver unit 70 has two switches and isassociated with each fixture, and each ballast (with its associatedlamps on the fixture) is independently controlled by one of the switchesin the transceiver unit 70. Each local transceiver unit 70 may becoupled to its associated HIF lighting fixture 60 in any one of avariety of manners. For example, the local transceiver unit may belocally installed adjacent to the HIF lighting fixture and hard-wired(e.g. for retro-fit applications, etc.). According to another example,the local transceiver unit may be configured for plug-in connection tothe HIF lighting fixtures (e.g. in a “plug-and-play” manner, etc.).According to a further example, the local transceiver unit may beintegrally formed with (or otherwise integrally provided as a part orcomponent of) the HIF lighting fixtures.

According to one embodiment as shown for example in FIG. 2-3, the HIFlighting fixtures 60 form an artificial lighting system for interiorspace 16 in the facility 12. According to an alternative embodiment, theelectrical equipment may be any of a wide variety of energy consumingdevices or equipment, such as appliances, motors that operate buildingservice loads or run manufacturing process equipment, etc.).

As illustrated in FIGS. 2-3, the master controller 20 receives thesensor output signal 52 representative of motion (e.g. by occupantswithin the facility, operation of manufacturing equipment, etc.) and/orambient light level (e.g. artificial light from fixtures that are “on”,natural light such as sunlight through windows, skylights, light pipes,etc.) from the sensor(s) 50. The master controller 20 also receives aresponse signal 72 from the local transceiver unit 70 associated witheach HIF lighting fixtures 60 indicating whether the fixture 60 (or it'sballasts) is “on” or “off.” The master controller 20 processes thesensor output signal 52 from the sensor 50 and the response signal 72from local transceiver units 70 according to a preprogrammed method oralgorithm and determines whether a demand for lighting exists within theinterior space 16, and then provides an appropriate demand-based controlsignal(s) 44 to the local transceiver unit(s) 70 for operation of theHIF lighting fixtures 60.

For example, the method for determination of artificial lighting demandin the interior space 16 may include the steps of (a) comparing theambient light level to a predetermined setpoint, below which artificiallighting is desired and above which artificial lighting is not desired,(b) determining whether motion within the environment is present. If thelight level is below the setpoint, and the HIF lighting fixtures 60 are“off,” and motion is detected, then the master controller 20 generates ademand-based control signal 44 that is transmitted from the mastertransceiver 40 to the appropriate local transceiver units 70 to turn HIFlighting fixtures 60 (e.g. one or both ballasts) “on”. The localtransceiver units 70 receive the demand-based control signal 44 andoperate to turn their respective HIF lighting fixtures 60 “on” and thensend a respond signal 72 to the master controller 20 to provide thestatus of each HIF lighting fixture 60 (e.g. “on”). Similarly, if theambient light level within the environment is above the setpoint and theHIF lighting fixtures 60 are “on”, regardless whether or not motion isdetected, then the master controller 20 provides a demand-based controlsignal 44 to the local transceiver units 70 to turn fixtures 60 “off”.The master controller 20 may delay the control signal for a suitabletime delay period (e.g. 5 minutes, 15 minutes, etc.) to provideincreased assurance that no activity in the environment is present (e.g.to avoid a “strobe” or “disco” like effect resulting from turning thefixtures on and off in response to intermittently changing lightlevels—such as intermittent cloud cover, etc.). The master controller 20may also be programmed to provide a time delay before such fixtures maybe turned back on again (e.g. to minimize power consumption associatedwith too-frequently cycling the equipment or fixtures between and on andoff condition, and/or to minimize detrimental effects on the equipmentsuch as reducing lamp life, overheating motors, etc.). The localtransceiver units 70 receive the demand-based control signal 44 andoperate (e.g. by actuating one or more switches or relays) to turn theirrespective HIF lighting fixtures 60 “off” and provide a response signal72 to the master controller 20 indicating the status (e.g. “on” or“off”) of the fixture 60, thus providing “metering” of the HIF lightingat a “fixture level.”

The master controller 20 “meters” the amount of the power reductionachieved (during peak demand and off-peak demand periods) by logging theresponse signal 72 of the HIF lighting fixtures' status received fromthe local transceiver units 70 and providing cumulative data on thetime, duration and status of the HIF lighting fixtures 60. The data maybe provided on a predetermined frequency (e.g. monthly or keyed on someother criteria, such as a billing period, etc.).

According to an alternative embodiment shown in FIG. 3, the sensor 50for a particular environment may interface directly with one of thelocal transceiver units 70 for the HIF lighting fixtures 60 associatedwith the interior space 16. The local transceiver unit 70 thenwirelessly transmits the sensor output signal 52 from the sensor(s) 50to the master controller 20. For example, a sensor may include a modularquick-connect that plugs into a local transceiver unit, or may behard-wired to the local transceiver unit, or may transmit the sensorsignal wirelessly to the local transceiver unit. In either case, thelocal transceiver unit “relays” the sensor signal to the mastercontroller.

The master controller also operates to accomplish peak demand energyreduction by receiving override control signals (e.g. to turn-offcertain fixtures according to a predetermined scheme) from the powerprovider (in response to peak demand management or shapingobjectives/criteria) and transmitting a signal to appropriate localtransceivers to “override” any existing or previous signal and turn-offthe associated HIF fixture (or a ballast of the fixture). For such“override” modes of operation where the master controller 20 provides asignal that overrides the “normal” mode of monitoring and controllingoperation of the HIF lighting fixtures 60, such as when override controlinstructions are received from a user (e.g. power provider 14, afacility manager, or the like to shed or trim loads to manageelectricity usage during peak demand periods, etc.), the mastercontroller 20 receives input signals or instructions 17 (manually orautomatically) to control operation of the HIF lighting fixtures 60. Forexample, during periods when available electric capacity is limited anda power provider 14 (e.g. an independent system operator, etc.) desiresto selectively reduce system-wide loading to maintain stability of aregional electric grid, the power provider may manually sendinstructions 17 to the master controller 20 to reduce power consumptionby a specified amount (e.g. percent load, specific number of kilowatts,etc.). According to another embodiment for managing electricity usageduring peak demand periods, the instructions 17 may be providedautomatically (e.g. by a automatically initiated and signal sent to themaster controller) in response to certain predetermined conditions,occurrences, or criteria (e.g. existing demand is approaching (or hasexceeded) a predetermined level such as a percentage of grid capacity,or a rate of increase of demand is approaching (or has exceeded) as apredetermined level, or a loss of certain generating capacity hasoccurred or is anticipated, etc.), and are received by the mastercontroller 20 to implement the instructions and “override” existingequipment control status (if necessary). The master controller 20processes the instructions 17 according to a preprogrammed algorithmthat reflects the criteria established and agreed upon between the powerprovider and the facility manager for intervention (or interruption) bythe power provider. According to another embodiment, the overridecontrol signal 46 may be manually initiated by the facility manager(e.g. by actuating an input interface (touch screen, pushbutton, etc.)at, or operably associated with, the master controller) to permit thefacility manager to initiate action (unilaterally or in coordinationwith a power provider) to reduce peak demand.

According to one embodiment, the algorithm reads the desired loadreduction instructed by the power provider 14 and identifies certain HIFlighting fixtures 60 to be turned-off according to a preprogrammedhierarchy of fixtures that are arranged generally from least-critical tomost-critical for the operation or purpose of the facility 12,corresponding to the amount of load reduction requested by the powerprovider 14. The master controller 20 defines or provides an overridesignal 46 to be transmitted by the master transceiver 40 to theappropriate local transceiver units 70 to turn off the corresponding HIFlighting fixtures 60 identified by the master controller 20 to complywith the instructions 17. The local transceiver units 70 operate to turnthe HIF lighting fixtures 60 off and then send a response signal 72 tothe master controller 20 with the status of the HIF lighting fixtures 60(i.e. “off”). The master controller 20 may process one or moreiterations of load shedding control signals to local transceiver units70 until the amount of load reduction requested by the power provider 14has been achieved. The master controller 20 logs the status of the HIFlighting fixtures 60 and sends data 18 (e.g. “instantaneously” orotherwise within a certain desired time period) to the power provider 14confirming the instructions and identifying the equipment status and thecorresponding amount of power reduction (i.e. “instantaneous metering”or the like), where the dynamics of regional grid stability and controldictate a rapid instruction and response.

Upon restoration of the system condition (e.g. grid stability, desiredcapacity margins, etc.) the power provider 14 may then send instructions17 to the master controller to resume a normal mode of operation for theHIF lighting fixtures 60 (as otherwise indicated by time-based ordemand-based criteria). Alternatively, in the event that overrideoperation was initiated within the facility (e.g. by a facility manager,etc.), the facility manager may provide instructions to the mastercontroller (e.g. via an input interface on the master controller, etc).The master controller 20 then operates to restore such loads (if needed)according to the algorithm for the normal mode of operation, includingsuch factors as the facility's usage pattern, the sensor signals, theexisting status of the HIF lighting fixtures, etc., preferably byrestoring the HIF lighting fixtures in order from most-critical toleast-critical.

During any mode of operation, the master controller 20 monitors thestatus of the HIF lighting fixtures 60 and records the time (e.g. dateand time) that the devices turn on and off, and determines the amount oftime that the device was actually “off” during the normal “on” time ofthe facility's usage pattern and calculates the amount of peak demandelectrical energy saved, based on pre-programmed data related to eachfixture's electrical power consumption rating. The calculation of peakdemand electrical energy saved may be conducted on a daily basis, or maybe done on a less frequent and cumulative basis (e.g., weekly, monthly,etc.).

According to one embodiment, the master controller 20 also sends thedata 18 representing the peak demand power reduction to the facility'spower provider 14, so that an appropriate credit for reduction in peakdemand power may be received by the facility owner (or itsrepresentative). The applicants believe that large-scale implementationof the intelligent monitoring, controlling and metering system and the“override” ability to shed a facility's loads when necessary in apredetermined manner could provide substantial reductions in peak powerdemand, and permit the power provider to better manage limited powerresources during peak periods. Such peak demand reductions are intendedto minimize the need for constructing new power generating plants, whichcould provide substantial economic savings/benefit. However, in orderfor demand-side users of the power to implement peak demand powerconsumption reduction measures such as intelligent monitoring andmetering, business models typically require some type of incentive to beprovided to the user. One possibility is that the power provider couldprovide certain on-going credits (e.g. discounts, rebates, refunds,etc.) corresponding to the peak demand power reduction achieved by theuser, in order to provide incentive. The master controller is intendedto allow demand-side users to intelligently manage their power usage andobtain corresponding credits, while permitting the supply-side powerproviders to obtain the benefits of a lower peak demand, by activelycontrolling operation of the electrically-operated equipment, andrecording and storing the equipment's operating status data, andcalculating the resulting reduction in peak power demand, andtransmitting such data to the power provider.

Referring further to FIG. 2, the master controller 20 is described infurther detail, according to an exemplary embodiment. Master controller20 is shown to include a display 22, an input interface 24, an outputinterface 26, a memory 28, a processor 30, a normal mode equipmentcontroller application 32, an override mode equipment controlapplication 34, a power reduction metering application 36 and a usagepattern application 38. However, different and additional components maybe incorporated into master controller. Display 22 presents informationto a user of master controller 20 as known to those skilled in the art.For example, display 22 may be a thin film transistor display, a lightemitting diode display, a liquid crystal display, or any of a variety ofdifferent displays known to those skilled in the art now or in thefuture.

Input interface 24 provides an interface for receiving information fromthe user for entry into master controller 20 as known to those skilledin the art. Input interface 24 may use various input technologiesincluding, but not limited to, a keypad, a keyboard, a pen and touchscreen, a mouse, a track ball, a touch screen, one or more buttons, arotary dial, etc. to allow the user to enter information into mastercontroller 20 or to make selections presented in a user interfacedisplayed on display 22. Input interface 24 is also configured toreceive signals from a power provider 14 (e.g. override instructions toreduce load, etc.). Input interface 24 is also configured to receiveresponse signals 72 from the local transceiver units 70 representativeof a status of their associated HIF lighting fixtures 60. Outputinterface 26 provides the control signals to the master transceiver 40,and sends metering data 18 to a user (e.g. transmits instantaneousmonitoring and metering data to a power provider 14 in response tooverride instructions, or transmits power reduction metering data for apredetermined period of time to the power provider 14, etc.). Accordingto other embodiments, the input interface 24 may provide both an inputand an output interface. For example, a touch screen both allows userinput and presents output to the user. Master controller 20 may have oneor more input interfaces and/or output interfaces that use the same or adifferent technology.

Memory 28 is an electronic holding place or storage for information sothat the information can be accessed by processor 30 as known to thoseskilled in the art. Master controller 20 may have one or more memoriesthat use the same or a different memory technology. Memory technologiesinclude, but are not limited to, any type of RAM, any type of ROM, anytype of flash memory, etc. Master controller 20 also may have one ormore drives that support the loading of a memory media such as a compactdisk, digital video disk, or a flash stick.

Master transceiver 40 provides an interface for receiving andtransmitting data between devices (e.g. master controller 50, sensors50, local transceiver units 70, etc.) using various protocols,transmission technologies, and media as known to those skilled in theart. The communication interface may support communication using varioustransmission media that may be wired or wireless. Master controller 20may include a plurality of communication interfaces that use the same ora different transmission and receiving technology.

Processor 30 executes instructions as known to those skilled in the art.The instructions may be carried out by a special purpose computer, logiccircuits, or hardware circuits. Thus, processor 30 may be implemented inhardware, firmware, software, or any combination of these methods. Theterm “execution” is the process of running an application or thecarrying out of the operation called for by an instruction or algorithm.The instructions or algorithm may be written using one or moreprogramming language, scripting language, assembly language, etc.Processor 30 executes an instruction, meaning that it performs theoperations called for by that instruction. Processor 30 operably coupleswith display 22, with input interface 24, with output interface 26, andwith memory 28 to receive, to send, and to process information.Processor 30 may retrieve a set of instructions from a permanent memorydevice and copy the instructions in an executable form to a temporarymemory device that is generally some form of RAM. Master controller 20may include a plurality of processors that use the same or a differentprocessing technology.

Normal mode equipment controller application 32 performs operationsassociated with managing electricity usage during peak demand andoff-peak demand periods by controlling the operation of HIF lightingfixtures 60 in the facility 12 (such as a light level within theinterior space 16). Control of the HIF lighting fixtures 60 may bedetermined according to a time-based control algorithm (e.g. based on ausage pattern) and a demand-based control algorithm (e.g. based on inputsignals from sensor(s) that monitor applicable parameters or conditionssuch as light level and motion). The operations may be implemented usinghardware, firmware, software, or any combination of these methods. Withreference to the exemplary embodiment of FIG. 2, normal mode equipmentcontroller application 32 is implemented in software stored in memory 28and accessible by processor 30 for execution of the instructions thatembody the operations of normal mode equipment controller application32. Normal mode equipment controller application 32 may be written usingone or more programming languages, assembly languages, scriptinglanguages, etc.

Override mode equipment controller application 34 performs operationsassociated with reducing electricity usage during peak demand periods byoverriding the normal operation of HIF lighting fixtures 60 in thefacility 12 (such as reducing or shedding loads in the facility 12 inresponse to instructions 17 generated automatically or manually andreceived from a power provider 14, or the facility manager, etc.). Theoperations may be implemented using hardware, firmware, software, or anycombination of these methods. With reference to the exemplary embodimentof FIG. 2, override mode equipment controller application 34 isimplemented in software stored in memory 28 and accessible by processor30 for execution of the instructions that embody the operations ofoverride mode equipment controller application 34. Override modeequipment controller application 34 may be written using one or moreprogramming languages, assembly languages, scripting languages, etc.

Power reduction metering application 36 performs operations associatedwith calculating the amount of electric power saved during peak andoff-peak demand periods by controlling the usage of the HIF lightingfixtures 60 within the facility 12. The operations may be implementedusing hardware, firmware, software, or any combination of these methods.With reference to the exemplary embodiment of FIG. 2, power reductionmetering application 36 is implemented in software stored in memory 28and accessible by processor 30 for execution of the instructions thatembody the operations of power reduction metering application 36. Powerreduction metering application 36 may be written using one or moreprogramming languages, assembly languages, scripting languages, etc.

Facility usage pattern application 38 performs operations associatedwith establishing or providing the normal usage pattern (e.g. timeschedule and status such as “on” or “off”) of the HIF lighting fixtures60 in the facility 12, for use in calculating the amount of electricpower saved during peak and off-peak demand periods by controlling theusage of the HIF lighting fixtures 60 within the facility 12. Accordingto one embodiment, the facility usage pattern application 38 alsoincludes power consumption ratings for the HIF lighting fixtures 60controlled by the master controller 20. The operations may beimplemented using hardware, firmware, software, or any combination ofthese methods. With reference to the exemplary embodiment of FIG. 2,facility usage pattern application 38 is implemented in software storedin memory 28 and accessible by processor 30 for execution of theinstructions that embody the operations of peak demand power savedapplication 38. Peak demand power saved application 38 may be writtenusing one or more programming languages, assembly languages, scriptinglanguages, etc.

Referring further to FIG. 2, the HIF lighting fixtures 60 may be thesame or may include variations of HIF lighting devices. Associated witheach of the plurality of HIF lighting fixtures 62 is a local transceiver70 having a unique address recognized by the master controller 20, andwhich receives and responds to a control signal (42, 44, 46) from mastertransceiver 40. The control signal (42, 44, 46) may include a lightingindicator specific to each of the plurality of HIF lighting fixtures 60or may include the same lighting indicator for each of the plurality ofHIF lighting fixtures 60. The lighting indicator may indicate on/off ormay indicate a lighting level (e.g. turn one or both ballasts of afluorescent lighting fixture on or off).

According to one embodiment, the local transceiver units 70 are capableof plugging into the lighting fixtures (or other electrically operatedequipment provided by any of a wide variety of manufacturers) withoutadditional wiring and can communicate (e.g. receive and respond)wirelessly with the master controller 20 using radio frequency (e.g. 915MHz). Each local transceiver unit is assigned a unique address, so thateach fixture is identifiable to (and controllable by) the mastercontroller 20.

According to one embodiment, master transceiver 40 transmits controlsignal 42, 44, 46 using a radio frequency (such as 915 MHz) to the localtransceiver units 70 of the interior space 16 that are within aneffective range R1 defined based on the characteristics of thetransmitter as known to those skilled in the art. However any of a widevariety of operating frequencies, modulation schemes, and transmissionpower levels can be used. For example, frequencies in the range of27-930 MHz, and particularly within about 5% of 315, 434, 868, and/or915 MHz may be used. Additionally, other frequencies such as 2.4gigahertz may be used. Master transceiver 40 and local transceiver units70 may be designed to qualify as unlicensed radio frequency devicesunder the Federal Communications Commission rules found in 47 C.F.R.§15. Master controller 20 is configured to encode a particulartransceiver address in the control signal 42, 44, 46. Each localtransceiver unit 70 is configured to respond only to control signals 42,44, 46 encoded with its unique address. The HIF lighting fixture 60associated with each local transceiver unit 70 can be turned on or off(or dimmed by de-energizing only one ballast) based on the controlsignal 42, 44, 46 received from the master transceiver 40. The addressinformation may be encoded in the control signal using a variety ofmethods as known to those skilled in the art.

Referring further to FIG. 2, the master controller 20 can control theHIF lighting fixtures 60 located throughout the facility 12, by usingone or more of the local transceiver units 70 as “repeaters” (shown as arepeater 74) to overcome range limitations due to the distance of thedesired equipment from the master transceiver 40. For example, mastertransceiver 40 transmits a control signal 42, 44, 46 within a firstrange R1 for operation of fixtures 60 that are within range R1. A localtransceiver unit 70 positioned within effective range R1 is designated(i.e. preprogrammed) to also operate as a repeater 74 by receiving thesignal 42, 44, 46 from master transceiver 40 and retransmitting thecontrol signal 42, 44, 46 using a radio frequency (e.g. 915 MHz) to anylocal transceiver units 70 within a repeater effective range R2. Usingthe local transceiver unit 70 as a repeater 74, the group of equipment60 (shown for example as light fixtures 62) positioned outside effectiverange R1 (and within the effective range R2) can be controlled. Althoughonly one repeater has been shown, multiple repeaters may be provided topermit control of a wide variety of electrically operated equipmentlocated in various interior spaces throughout the facility.

Referring to FIG. 4, the method of monitoring, controlling and meteringthe HIF lighting fixtures in the facility is shown according to oneembodiment to include the following steps (among possible other steps):

(a) establishing a usage pattern that defines a time-based controlscheme for operation of designated HIF lighting fixtures within anenvironment of a facility,

(b) providing a time-based control signal to the HIF lighting fixturesto operate according to the time-based control scheme,

(c) modifying the time-based control scheme by monitoring a signalrepresentative of one or more parameter in the environment and providinga demand-based control signal to one or more of the HIF lightingfixtures,

(d) receiving override instructions from a power provider to reduceelectrical loading at the facility,

(e) providing an override control signal to one or more of the HIFlighting fixtures to accomplish the override instructions,

(f) receiving a response signal representative of a status of each ofthe HIF lighting fixtures in response to the control signals,

(g) sending a confirmation signal to the power provider in response tothe override instructions, the confirmation signal including datarepresentative of the identity and status of the HIF lighting fixturesthat received the override control signal,

(h) logging the status, time and duration of operation (ornon-operation) of each of the HIF lighting fixtures,

(i) quantifying a reduction in the power usage achieved by operating theHIF lighting fixtures according to the control signals, and

(j) sending a report containing data representative of the reduction inpower usage over a predetermined time period to a power provider.

However, any one or more of a variety of other steps may be included, inany particular order to accomplish the method of monitoring, controllingand metering operation of the HIF lighting fixtures in the facility.

Referring to FIG. 5, the method of reducing electricity usage duringpeak demand periods by monitoring, controlling and metering the HIFlighting fixtures in the facility is shown according to one embodimentto include the following steps (among possible other steps):

(a) establishing a set of predetermined load reduction criteria that arerepresentative of a need or desire by a power provider to reduce loadingon an electricity supply grid during peak demand periods; the criteriamay include a level or amount of load/demand on the grid, or a rate ofincrease in load/demand on the grid, or an actual or anticipatedreduction in electricity supply to the grid, or a level or amount ofcapacity available on the grid, or a rate of decrease in the capacityavailable on the grid, where capacity is generally understood to be thedifference between the available supply of electricity to the grid andthe demand (i.e. load, etc.) on the grid (e.g. by users connected to thegrid, etc.),

(b) establishing an agreement with a facility manager to facilitate thepower provider's ability to manage the peak demand on the grid andintervene by interrupting the operation of certain HIF lightingequipment in the facility by sending instructions (manually orautomatically) to a master controller in the facility; the instructionsmay designate specific equipment to be turned-off, or may specify anamount of electricity usage reduction to be achieved at the facility;the instructions may be initiated manually on an as-needed basis, or themay be initiated automatically in response to the occurrence of one ormore of the predetermined load reduction criteria; where theinstructions may identify specific HIF lighting equipment to beturned-off (e.g. according to a unique address for a local transceiverassociated with the specific HIF lighting equipment), or specify anamount of load reduction requested by the power provider,

(c) establishing a schedule or listing of HIF lighting equipment in thefacility to be turned-off in response to the instructions; the listingof equipment may be include individual fixtures, or independent ballastswithin a fixture, identified by a unique address recognized by themaster controller; the fixtures may be groups of fixtures based onlocation or criticality to operation of the facility; the groups offixtures may be specified in a cascading hierarchy of groups that areturned-off sequentially, or simultaneously, depending on an amount ofelectricity usage reduction, or the specific fixtures/ballasts,identified by the instructions;

(d) configuring the master controller (or an associated device) to sendan override control signal to each of the designated HIF lightingdevices; where the master controller may communicate with a mastertransceiver that communicates with a local transceiver associated witheach lighting device (or a designated group of lighting devices to beoperated collectively as a single unit),

(e) monitoring a status of the capacity of, or demand on, an electricitysupply grid or network,

(f) sending an override control signal in response to the instructionsreceived upon the occurrence of any one or more of the predeterminedload reduction criteria;

(g) turning-off certain HIF lighting equipment in response to theoverride control signal;

(h) sending a response signal from the local transceivers associatedwith the HIF lighting equipment confirming that the fixtures are “off”;

(i) quantifying (i.e. metering, etc.) an amount of electricity usagereduction achieved during a peak demand period by turning-off the HIFlighting equipment in response to the instructions from the powerprovider.

According to any exemplary embodiment, a system and method are providedfor reducing electricity usage during peak and off-peak demand periodsthrough intelligent monitoring, control and metering of HIF lightingfixtures within a facility. The system includes a master controller, amaster transceiver, one or more sensors, and a local transceiver unituniquely identifiable to the master controller for each of the HIFlighting fixtures in the facility to be controlled. The sensor(s)monitor parameters within the facility and provide sensor signal(s)representative of the parameters to the master controller. During anormal mode of operation, the master controller processes the sensorsignals according to preprogrammed algorithms and define or generatesignals that are transmitted from the master transceiver to theappropriate local transceiver unit(s) to control operation of the HIFlighting fixtures. The local transceiver units provide a response signalto the master controller indicating the status of the associated HIFlighting fixtures for logging and tracking by the master controller. Themaster controller provides power reduction metering data to a user forquantifying the power saved and the economic benefit resulting from thepower saved. During an override mode of operation, an outside user (e.g.power provider, facility manager, etc.) may manage the peak demand onthe electric grid by providing instructions (manually or automatically)to reduce or shed load at the facility. The instructions may be generic(e.g. reduce power by a certain amount or percentage) or theinstructions may be directed to certain identified equipment. The mastercontroller processes the instructions according to preprogrammedalgorithms and defines or generates signals that override previouscontrol signals and are transmitted from the master transceiver to theappropriate local transceiver unit(s) to provide override controloperation of the HIF lighting fixtures. The local transceiver unitsprovide a response signal to the master controller indicating the statusof the associated HIF lighting fixtures for logging and tracking by themaster controller. The master controller provides instantaneous meteringdata to the power provider to confirm implementation of the instructionsand identify a corresponding economic benefit resulting from the powersaved. According to alternative embodiments, the system and methoddescribed herein may be adapted for use with other types of electricallyoperated equipment within the facility, such as equipment related tomanufacturing processes, building support and services, and the like.

Accordingly, the intelligent monitoring, controlling and metering of theHIF lighting equipment in a facility is provided by the mastercontroller and includes preprogrammed instructions, algorithms, data andother information that permits the HIF lighting equipment to becontrolled (e.g. turned-off) in response to commands from an externalsource (e.g. a power provider), or an internal source (e.g. a facilitymanager), or in response to signals received from suitable sensors, toprovide optimum operation of the HIF lighting equipment in coordinationwith peak-demand conditions, and to reduce overall energy usage andimpact on the environment, and to optimize performance and life of theHIF lighting equipment and reduce maintenance and costs associated withthe lighting equipment.

The foregoing description of exemplary embodiments of the invention havebeen presented for purposes of illustration and of description. It isnot intended to be exhaustive or to limit the invention to the preciseform disclosed, and modifications and variations are possible in lightof the above teachings or may be acquired from practice of theinvention. The functionality described may be distributed among modulesthat differ in number and distribution of functionality from thosedescribed herein. Additionally, the order of execution of the functionsmay be changed depending on the embodiment. The embodiments were chosenand described in order to explain the principles of the invention and aspractical applications of the invention to enable one skilled in the artto utilize the invention in various embodiments and with variousmodifications as suited to the particular use contemplated. It isintended that the scope of the invention be defined by the claimsappended hereto and their equivalents.

The order or sequence of any process or method steps may be varied orre-sequenced according to alternative embodiments. Anymeans-plus-function clause is intended to cover the structures describedherein as performing the recited function and not only structuralequivalents but also equivalent structures. Other substitutions,modifications, changes and omissions may be made in the design,operating configuration and arrangement of the preferred and otherexemplary embodiments without departing from the spirit of theinventions as expressed herein.

What is claimed is:
 1. A method for metering energy use in a facilityhaving a plurality of lighting fixtures, comprising: wirelesslytransmitting an override signal from a first lighting fixture to a firstgroup of lighting fixtures within a first transmission range; receivingthe override signal at the first group of lighting fixtures; wirelesslyretransmitting the override signal from one or more of the first groupof lighting fixtures to a second group of lighting fixtures within asecond transmission range, wherein the second transmission range isoutside of the transmission range of the first lighting fixture;receiving the retransmitted override signal at the second group oflighting fixtures and, in response to the retransmitted override signal:(a) conducting an override at the second group of lighting fixtures and(b) reporting a status update from each of the second group of lightingfixtures to a master controller via at least one retransmission by oneor more of the first group of lighting fixtures; metering lightingsystem energy usage using at least the status information from thesecond group of lighting fixtures retransmitted to the master controllerby the one or more of the first group of lighting fixtures; evaluatingan ambient light level near the first lighting fixture using a sensorcoupled to control circuitry local to the first lighting fixture,wherein the first lighting fixture wirelessly transmits the overridesignal based on the evaluated ambient light level, and wherein at leastone lighting fixture of the first group of lighting fixtures and thesecond group of lighting fixtures retransmits the override signal to themaster controller.
 2. The method of claim 1, wherein metering lightingsystem energy usage comprises: monitoring the status of the plurality oflighting fixtures by recording one or more times that each lightingfixture transitions from on to off and from off to on.
 3. The method ofclaim 2, wherein metering lighting system energy usage furthercomprises: determining an amount of time that each lighting fixture wasactually off during a normally scheduled on time due to the overridesignal.
 4. The method of claim 3, wherein the metering does not includeusing energy metering devices on power lines of the lighting system. 5.The method of claim 3, wherein metering lighting system energy usagefurther comprises: calculating the amount of energy saved based on eachlighting fixture's electrical power consumption rating applied over theamount of time that each lighting fixture was actually off during anormally scheduled on time due to the override signal.
 6. The method ofclaim 5, further comprising: using the recorded times to controllablycause a time delay to elapse before a lighting fixture of the pluralityof lighting fixtures is cycled on again after it has been turned off. 7.A system for metering energy use in a facility having a plurality oflighting fixtures, comprising: a first group of lighting fixturesincluding a first lighting fixture; a master controller configured towirelessly transmit an override signal to the first group of lightingfixtures within a wireless transmission range of the master controller;a second group of lighting fixtures outside the wireless transmissionrange of the master controller; wherein one or more lighting fixtures ofthe first group of lighting fixtures are configured to retransmit theoverride signal received from the master controller to the second groupof lighting fixtures; wherein the second group of lighting fixtures areconfigured to, in response to receiving the retransmitted overridesignal, conduct an override of normal operation and report a statusupdate to the master controller via at least one retransmission by oneor more of the first group of lighting fixtures; wherein the mastercontroller is configured to meter lighting system energy usage using atleast the status information from the second group of lighting fixturesretransmitted to the master controller by the one or more lightingfixtures of the first group of lighting fixtures wherein the mastercontroller is configured to evaluate an ambient light level near thefirst lighting fixture using a sensor coupled to control circuitry localto the first lighting fixture, and wherein the master controllerwirelessly transmits the override signal based on the evaluated ambientlight level.
 8. The system of claim 7, wherein the master controllermeters lighting system energy without using energy metering devices onpower lines of the lighting system.
 9. The system of claim 7, whereinthe master controller is configured to monitor the status of theplurality of lighting fixtures by recording the times that each lightingfixture transitions from on to off and from off to on.
 10. The system ofclaim 9, wherein the master controller is further configured todetermine an amount of time that each lighting fixture was actually offduring a normally scheduled on time due to the override signal.
 11. Thesystem of claim 10, wherein the master controller is configured tocalculate the amount of energy saved based on each lighting fixture'selectrical power consumption rating applied over the amount of time thateach lighting fixture was actually off during a normally scheduled ontime due to the override signal.
 12. The system of claim 11, wherein themaster controller is further configured to use the recorded times tocontrollably cause a time delay to elapse before a lighting fixture ofthe plurality of lighting fixtures is cycled on again after it has beenturned off.